Stephens 1991.

Methods	Randomised, cross‐over trial; total of 6 months follow‐up
Participants	Location: UK (Wales); Welsh Institute of Hearing Research Setting of recruitment and treatment: patients from 2 general practices responded to a hearing disability questionnaire indicating a disability (588 responded out of 604 asked) and were invited for audiological assessment (289 assessed); 49 were eligible but 11 (22%) refused participation Sample size: Number randomised: 38 out of 49 eligible patients (11 refused participation) Number completed: 29 Participant (baseline) characteristics: Age: 50 to 65 years Gender: 23 male, 6 female Ethnicity: not stated Main diagnosis: bilateral hearing impairment Other important effect modifiers: Hearing loss status: bilateral hearing impairment equal to or worse than 30 dB HL (average over 0.5 kHz, 1 kHz, 2 kHz and 4 kHz) in the better ear Degree of asymmetry: asymmetrical hearing loss patients included Whether participants had previous experience of hearing aid use: no patients had previously used a hearing aid Cognitive impairment: not stated Visual impairment: not stated Presence of tinnitus: percentage not stated Inclusion criteria: aged 50 to 65 years, a bilateral hearing impairment equal to or worse than 30 dB HL (average over 0.5 kHz, 1 kHz, 2 kHz and 4 kHz) in the better ear and had not previously used hearing aids Exclusion criteria: previous hearing aid use
Interventions	Intervention groups (total n = 29 completed): Intervention 1: binaural hearing aids (4 to 6 weeks) Intervention 2: monaural hearing aids to preferred ear (4 to 6 weeks) Patients crossed over to the other arm after the 4‐ to 6‐week period Type of hearing aid fitted: UK National Health Service BE 18 post‐aural hearing aids with appropriate ear moulds, vented or open as individually indicated
Outcomes	Primary outcomes Patient preference for bilateral versus unilateral aids Secondary outcomes Speech in noise using FAAF at a signal ratio of 0 dB Sound localisation
Funding sources	Welsh Institute of Hearing Research and the MRC Institute of Hearing Research
Declarations of interest	No information provided
Notes	Hearing‐specific health‐related quality of life ‐ Social Hearing Handicap Index (SHHI) & Emotional Response to Hearing Loss (ERS) measured after preferences were reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation not stated. Numbers of patients in each of the 2 arms not stated. No data reported to demonstrate that the variables that might affect the outcomes were evenly distributed.
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	No information about blinding or fitting protocol provided
Blinding of outcome assessment (detection bias) All outcomes	High risk	All outcomes were patient‐reported
Incomplete outcome data (attrition bias) All outcomes	High risk	76% of patients (29 of 38) completed the study for the 6‐month follow‐up (preference data). The number of participants excluded was high. For the 10‐year follow‐up the study reported that 29/41 were traced: 12/22 bilateral and 17/19 unilateral patients were still alive.
Selective reporting (reporting bias)	Unclear risk	Some scales (e.g. SHHI and ERS) were measured but only results at the end versus baseline (rather than between groups) were reported